1995-12-20 04:00:00 PDT SAN FRANCISCO -- San Francisco voters will be asked to approve a massive expansion of Moscone Center under a measure headed for the March ballot.

If approved, the $157 million bond measure would increase the center's meeting space by 300,000 square feet, or 50 percent of its current size. The new three-story building would be about the same size as the original center, now known as Moscone South, which opened in 1981. That center doubled in size in 1991, when The City built the Moscone North addition across the street.

Both buildings reach 95 percent occupancy, said John Marks, president of the Convention & Visitors Bureau, and The City turns away convention business because it lacks adequate facilities.

"We have not been able to accommodate them because we don't have the space they need or the dates," Marks said.

The proposed convention center is the lone bond measure placed by the supervisors on the March 1996 ballot. No other proposition is scheduled for the ballot, although supervisors have until Dec. 27 to put new ordinances or policy declarations before the voters.

Unlike the existing Moscone Center buildings, which connect underground and face each other across Howard Street, the expansion would be a free-standing building located a half-block away. City officials are eyeing a Howard Street parking lot owned by Hearst Corp., which owns The Examiner, for the site, said Ray Fong, project manager for the Moscone expansion.

The lot is on the north side of Howard between Fourth and Fifth streets.

No design has been created, but Fong said the building would include 160,000 square feet of exhibit hall space and 75,000 square feet of meeting rooms.

While operating the expanded Moscone Center will cost The City $3.1 million a year, Marks said the convention facilities more than paid for themselves.

"The convention space is almost a loss leader," said Marks. "We are very clear in our mission. The building is a lure to fill hotel rooms, which then makes the economic meter run."

A study conducted by outside consultants estimates the expansion will bring in millions of dollars of new revenue to The City's economy generated from new jobs, higher hotel occupancy and more spending at restaurants and stores.

The $157 million in bonds will be paid for by an increase in the hotel occupancy tax, which will rise from 12 to 14 percent if voters approve the measure.

Some worry that the bond measure, which will increase the city's debt limit, might hurt other proposed capital improvement projects, including the San Bruno Jail, the Youth Guidance Center and Laguna Honda Hospital. Those projects would have to compete for bonds before the city reaches its self-imposed debt limit.

Laura Wagner-Lockwood, director of public finance in the chief administrative officer's office, said the higher debt limit must be monitored, but shouldn't keep the city from investing in improvement projects.

"Not to invest in the city's infrastructure and economic development would be foolhardy in the long run," Wagner-Lockwood said. "If you are in debt, but your roof is leaking, you need to get your roof fixed. You may not be able to go on vacation, but you need to get your roof fixed." &lt;